Fluid distribution system

ABSTRACT

The present invention provides a method and apparatus for bulk fluid distribution. In particular, the invention provides a method and apparatus for distributing fluids in a semiconductor manufacturing plant (e.g. a 300 mm fab). The invention meets the performance and uptime requirements of semiconductor manufacturers including increased capacity and pressure control as compared to known fluid distribution systems, and can satisfy the requirements of “no single point failures” and “no planned downtime.”

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from U.S. Provisional Patent Application Ser. No. 60/795,730 filed Apr. 28, 2006.

FIELD OF THE INVENTION

The present invention relates to an apparatus and method for distributing a fluid to a point of use. More specifically, the present invention provides an apparatus, having no single point failures or planned downtime, and a method for distributing a fluid to a semiconductor process tool for semiconductor processing.

BACKGROUND OF THE INVENTION

The manufacture of semiconductor (i.e. integrated circuit) devices is a complex process involving hundreds of process steps. Each step requires optimal conditions to produce a high yield of the devices. In addition, many process steps require fluids to inter alia etch, expose, coat, and polish materials deposited on the surfaces of the devices during manufacturing. When high purity fluids (e.g. hydrofluoric acid, sulfuric acid, hydrogen peroxide, ammonium hydroxide and isopropyl alcohol) are used during the manufacturing process, the fluids must be substantially free of particulate and metal contaminants to prevent defects in the finished devices. When chemical-mechanical polishing slurries (e.g. Semi-Sperse®-12, iCue® 5001, Klebosol® 1501 and Cab-O-Sperse® SC-112) are used, the slurries must be free from large particles capable of scratching the surfaces of the devices and causing defects. Moreover, during manufacturing there must be a stable and sufficient supply of the fluids to the process tools to avoid process fluctuations and manufacturing downtime.

Since their introduction to the semiconductor market, bulk fluid distribution systems have played an important role in semiconductor manufacturing processes. Prior to the use of fluid distribution systems, process fluids were stored and transported to the process tools in plastic or glass bottles. This method involved many hazards in transportation and use such as broken bottles, chemical exposure to operators, and spilling or splashing when pouring the fluids into baths or other containers. In addition, there were several opportunities for the fluids to become contaminated through exposure to the atmosphere and contact with objects (e.g. operator gloves). Fluid distribution systems, such as the Model 1500 manufactured by the Chemical Management Division of BOC Edwards™, Inc., were developed to eliminate these hazards and contamination issues and to help automate the process of replenishing fluids in the manufacturing process. Notably, the Model 1500 has been used by semiconductor manufacturers for over a decade.

A representation of a typical fluid distribution system used in semiconductor manufacturing processes is shown in FIG. 1. The system 100 is a standalone unit including a controller 101, a human-machine interface (HMI) 103, an electrical compartment 105 including input/output (I/O) components and solenoid valves 106, connections to facilities such as clean dry air 107, nitrogen 109, exhaust 111, deionized water 113 and city water 115, an engine 117, and a day tank 123. The engine 117 is typically one of several types: 1) pump-pulse dampener; 2) pump-pressure vessel; or 3) alternating pressure vacuum vessel. FIG. 1 is shown with a pump-pulse dampener engine 119,121. During operation, system 100 draws fluid from supply drums 127 or a pressurized source and dispenses the fluid to one or more points of use 129.

The components of system 100 are enclosed in a stainless steel or polymer cabinet 125 and the system is substantially constructed of inert wetted materials to minimize particulate and metal contamination of the process fluids. While the bulk fluid distribution system 100 of FIG. 1 has eliminated the problems with bottle delivery and can distribute large volumes of fluid to the process tools, the fluid often meeting and exceeding the purity requirements of semiconductor manufacturers, system 100 also has drawbacks.

The fluid distribution system of FIG. 1 has several “single point failures” and requires “planned downtime.” A single point failure occurs when a vital component or function of the system fails thereby preventing the system from operating safely or from adequately dispensing fluid to the points of use. Planned downtime refers to the product maintenance schedule and how often the system must be shutdown to check or replace a component. For example, single point failures in system 100 include distribution valve 131, valve 133, controller 101, regulator 108 and pressure switches 112 a, 112 b and 112 c. If any of these components failed, then system 100 would either be unable to distribute fluid to the points of use or safely exhaust the cabinet compartments. Similarly, planned downtime schedules such as a monthly check of the pressure switches 112 a, 112 b and 112 c and a quarterly check of the valves 131 and 133 require shutdown of the entire system.

As a result of such limitations to existing designs, many semiconductor manufacturers require two fluid distribution systems per fluid stream in order to ensure complete redundancy. This solution is costly and inefficient with regard to space utilization. Some fluid distribution system designs address these issues in different ways. For example, one design provides redundant pump engines with independently serviceable cabinets. Other systems address redundancy and uptime by using dual pump engines whereby the system has the capability of switching from the on-line pump to the off-line pump when the on-line pump fails. These designs allow for limited maintenance of systems while they are operating. However, the dual pump engines are not equivalent—one engine is smaller than the other and complete serviceability and maintenance cannot be performed without system shutdown. Another design also provides redundant pumps, but in a shared cabinet. The filters are not redundant and the system has less redundancy options for maintenance and serviceability as compared to the first mentioned design. Yet another design offers considerable redundancy and good serviceability, but is costly due to excessive amounts of isolation in the system.

Thus, there is a need for a bulk fluid distribution system that substantially or completely eliminates single point failures and the impact of product maintenance shutdowns (i.e. “planned downtime”). In addition, there is a further need for a bulk fluid distribution system that is modular and has a smaller footprint as compared to the footprint of two distribution systems such as system 100 shown in FIG. 1.

BRIEF DESCRIPTION OF THE INVENTION

A fluid distribution system for supplying fluid to a point of use comprising a fluid source; a first engine adapted to receive fluid from the fluid source and to distribute fluid to the point of use; and a second engine identical to the first engine, the second engine being adapted to receive fluid from the fluid source and to distribute fluid to the point of use; wherein the fluid distribution system does not have any single point failures.

A method of distributing fluid to a point of use comprising distributing fluid to the point of use with a first engine; filtering fluid in a day tank with a second engine; and filtering fluid in a supply drum with a third engine; wherein each of the first, second and third engines is adapted to perform the steps of distributing fluid to the point of use, filtering fluid in the day tank and filtering fluid in the supply drum.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic representation of a known fluid distribution system.

FIG. 2 is a schematic representation of an embodiment of the bulk fluid distribution system of the present invention.

FIG. 3 is a schematic representation of an embodiment of an optional source management module of the present invention.

FIG. 4 is a schematic representation of an embodiment of the main module of the present invention.

FIG. 5 is a schematic representation of an embodiment of a pump-pressure vessel engine of the present invention.

FIG. 6 is a schematic representation of an embodiment of a pump pulse-dampener engine of the present invention.

FIG. 7 is a schematic representation of an embodiment of a centrifugal pump engine of the present invention.

FIG. 8 is a schematic representation of an embodiment of an alternating pressure vacuum vessel engine of the present invention.

FIG. 9 is a schematic representation of an optional day tank module of the present invention.

FIG. 10 is a schematic representation of floor space configurations for various embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides a method and apparatus for bulk fluid distribution. In particular, the invention provides a method and apparatus for distributing fluids in a semiconductor manufacturing plant (e.g. a 300 mm fab). The invention meets the performance and uptime requirements of semiconductor manufacturers including increased capacity and pressure control as compared to known fluid distribution systems, and can satisfy the requirements of “no single point failures” and “no planned downtime.”

An embodiment of a bulk fluid distribution system according to the present invention is shown in FIG. 2. Fluid distribution system 200 includes five subsystems: three engine modules 201, 203 and 205, one main module 207 and one source management module 209. Each subsystem can be maintained and repaired independent of the operation of the other subsystems. System 200 may be supplied by drums of source fluid 213 or by a pressurized supply line of source fluid and may optionally include a day tank module 211 containing a day tank for storing large quantities of fluid for distribution to points of use. Similarly, the main module 207 may also include the day tank in addition to sampling and facility connections. The controls in the main module have dedicated input-output (I/O) modules for each subsystem and the control system can be built around a single CPU (taking exception to the single point failure criteria) or dual CPUs. The engines 201, 203, and 205 may be identical to one another and can perform identical functions including distribution to the points of use, day tank polishing, drum polishing, drum switching or any combination thereof. The system also allows for complete isolation of each engine, including isolation of the electrical, controls, pneumatics and fluids compartments.

In one embodiment, facility supply lines 215, including compressed dry air 215 a, nitrogen 215 b, deionized water 215 c, city water 215 d and exhaust 215 e, and fluid dispense line 217 flow into and out of the main module 207. In another embodiment, the facility supply lines 215 may also flow into and out of each module 201, 203, 205, 209 and 211.

Fluid supply lines 219 a and 219 b are connected to the source management module 209 which distributes the source fluid to the main module 207. In one embodiment, each of the engines 201, 203 and 205 receives the source fluid from the main module 207 through, for example, bulk-heads or pass-throughs in the module cabinets. In another embodiment, the engine modules 201, 203 and 205 may receive the source fluid directly from the source management module 209.

The plumbing and instrumentation and operation of each module will be described separately with reference to FIGS. 3-8. A schematic diagram of the source management module 209 is shown in FIG. 3. The primary function of the source management module 209 is as a drum switching or supply line switching mechanism. In an embodiment where the source fluid is supplied by drums 213, each of the supply drums 213 is connected to the source management module 209 by fluid supply lines 219 a and 219 b. Each fluid supply line 219 a and 219 b includes a valve and is connected to the main module 207 via main supply line 220. Optionally, the source management module 209 may be connected to a main return line 221 from the main module 207. This option would enable drum polishing, that is, recirculating the fluid in the drum through a filter for a period of time to remove any particles resulting from shipment and manufacture of the fluid. Typically, this operation would occur every time an old drum was replaced with a new one and would be initiated by an operator through the HMI in the main module 207. Similarly, the controller in the main module 207 could be configured to cause a drum polish to occur on a periodic basis.

A schematic diagram of the main module 207 is shown in FIG. 4. The main module 207 houses the facilities connections including compressed dry air 215 a, nitrogen 215 b, deionized water 215 c, city water 215 d and exhaust 215 e, and fluid dispense line 217 (as shown in FIG. 2) and it houses the programmable logic controller (PLC) and HMI. The main module 207 may include two PLCs for redundancy or another PLC may be located elsewhere in or near the system 200. Optionally, the main module 207 will include a sample station for collecting samples of the fluid at various points within the system for analysis.

As mentioned above, the engines may all be identical so that each can perform the same operations thereby providing redundancy and serviceability and eliminating or substantially reducing single point failures and planned downtime. A single point failure occurs where a component in the fluid distribution system fails causing the entire system to shutdown and stop distributing fluid to the point of use. The failed component may be a valve in the distribution loop that mechanically prevents fluid flow or may be a valve in the system exhaust that prevents safely exhausting the cabinet. Planned downtime refers to the periodic maintenance schedule of components in the system; in prior art systems, if certain components must be replaced or serviced, the entire system must be shutdown. A system having no planned downtime is one where periodic maintenance may be performed on a system component without disrupting operation of the system, in particular, fluid distribution to the point of use.

Notably, all engines are capable of receiving fluid from the source drums through line 220, the main module 207, or from the day tank module 211. Furthermore, all of the engines dispense the fluid through a filter or a filter bank (i.e. two to four filters in parallel) and back to either the drums 213 or day tank module 211 or to the points of use 217. In addition, each engine is capable of distributing fluid to the points of use, polishing the fluid in the day tank (by filtering), polishing the fluid in the drums (by filtering), drum switching or any combination thereof.

FIG. 5 shows a first embodiment of engines 201, 203 or 205 according to the present invention. In the first embodiment, the engines are pump-pressure vessel engines. The pump 501 can be any type of positive displacement pump (e.g. an air-operated dual diaphragm pump, a self-reciprocating pump, a bellows pump, etc.). The pressure vessel 503 may be constructed of an inert wetted polymer material such as perfluoroalkoxy (PFA), polytetrafluoroethylene (PTFE), polyvinylchloride (PVC), polyvinylidine difluoride (PVDF), or polyethylene (PE). In addition, the vessel 503 must be able to withstand pressurization while dispensing the fluid to the points of use 217, the drums 213 or the day tank 211. An inert gas such as nitrogen may be used to pressurize the vessel 503 and thereby dispense the fluid. The nitrogen is preferably regulated with regulator 505 to provide appropriate control of the dispense pressure of the fluid. The vessel includes load cells 507 or capacitive, optical or digital sensors on a sight tube, to maintain the level of the fluid in the vessel between a high and low setpoint. The controller in the main module 207 controls this operation.

A second embodiment of the engine 201, 203 or 205 of the present invention is shown in FIG. 6. Like the pump-pressure vessel engine, the pump-pulse dampener engine of FIG. 6 includes a positive displacement pump 601. The pump-pulse dampener engine further includes a pulse dampener 603 facilitated with CDA 215 a. The pressure of the CDA 215 a is preferably regulated with regulator 605. As mentioned above, the pump-pulse dampener engine can receive fluid from the drums 213 or the day tank module 211 and distribute the fluid to the points of use 217 or back to the source management module 207, source line 220 or the day tank module 211.

A third embodiment of the engine 201, 203 or 205 of the present invention is shown in FIG. 7. In contrast to the pump-pressure vessel and pump-pulse dampener engines of FIGS. 5 and 6, the third embodiment is a centrifugal pump engine. In this embodiment the pump 701 is any centrifugal pump that is resistant to corrosion from fluids such as strong acids and bases (e.g. hydrofluoric acid, sulfuric acid, hydrochloric acid, hydrogen peroxide, ammonium hydroxide, etc.). The centrifugal pump 701 may be a magnetically levitated bearingless pump such as those manufactured by Levitronix® GmBH. Such pumps may include a designated controller 703 to control the speed of the pump. Such controller would preferably communicate with the main controller in the main module.

A fourth embodiment of the engine 201, 203 or 205 of the present invention is a pressure-vacuum vessel engine. The pressure-vacuum vessel engine includes two pressure-vacuum vessels 801, 802. Each vessel 801, 802 is equipped with at least two fluid level sensors 803, 804, 805, 806 such as capacitive, optical or digital sensors, or load cells. The sensors 803, 804, 805, 806 monitor the fluid level in the vessels 801, 802.

During a fill cycle, a vacuum-generating device 807, 808 (e.g. an aspirator or venturi) creates a vacuum in the vessel to draw in the fluid. When the vacuum is operated on a vessel, any gas in the vessel flows to an exhaust 215 e as the fluid from either the source line 220, the main module 207 or the day tank module 211 is drawn into the vessel. When the fluid level reaches a predetermined high level, the vacuum stops.

During a dispense cycle, an inert gas, such as nitrogen, flows through a “slave” regulator 809, 810 and into the dispensing vessel 801, 802. The vessel 801, 802 is initially pressurized to a predetermined pressure and then the fluid under the force of the inert gas pressure flows through the filter 811 and to the points of use 217, or back to the drums 213 or the day tank module 211. The vessel 801, 802 dispenses the fluid until it reaches a predetermined low fluid level at which point the fill cycle begins again.

During operation, the vessels 801, 802 alternate between fill and dispense cycles such that when one vessel is filling, the other vessel is dispensing. Notably, the vacuum-generating device 807, 808 is configured so that the vessels 801, 802 fill faster than they dispense to provide a continuous flow of fluid to the points of use or other areas in the system 211, 213.

FIG. 9 shows an embodiment of the optional day tank module 211. The day tank 901 may include load cells 903, 904 or capacitive, optical or digital sensors on sight tubes to monitor the level of fluid in the day tank. The day tank is typically constructed of an inert polymer such as PFA, PTFE, PVC, PVDF or PE.

Each engine 201, 203, 205 is capable of distributing fluid to the points of use, polishing the fluid in the day tank 901 (by filtering), polishing the fluid in the drums 213 (by filtering), drum switching or any combination thereof. When an engine distributes fluid to the points of use 217, it dispenses the fluid into either a global distribution loop that recirculates back to the fluid distribution system or to a dead-headed dispense line. Typically several semiconductor tools are teed into the global distribution loop or dispense line and demand fluid from these lines on a periodic or continuous basis. When fluid in the day tank 901 is polished, the engine 201, 203, 205 draws the fluid from the day tank 901 in the day tank module 211 and dispenses the fluid through a filter 811 and back into the day tank 901. The fluid is recirculated through the filter for a predetermined period of time (i.e. about 5-45 minutes). Similarly, the fluid in one of the drums 213 is polished when the engine 201, 203, 205 draws fluid from the drum and dispenses the fluid through the filter 811 and back into the drum. The fluid is recirculated through the filter and back to the drum for a predetermined period of time (i.e. about 5-45 minutes). The engine 201, 203, 205 can also send a signal to the controller 401 to effectuate drum switching. The engine 201, 203, 205 will send the signal when it detects that there is no fluid in the on-line drum. The controller 401 then closes the valve (e.g. 301) in the source management module 209 connected to the on-line drum and opens the valve (e.g. 303) connected to the off-line drum so as to switch between the drums.

Another important feature of the fluid distribution system according to the present invention is the configuration of the various modules in order to reduce floor space as compared to known fluid distribution systems. Embodiments of possible floor space configurations are shown in FIG. 10. In embodiment 10(a), the engines 201, 203 are positioned and accessible on one side of the system while the main module is positioned on the other side of the system. Notably, the main module 207 preferably has an electrical compartment 207 a for the electrical (i.e. solenoids), controls (i.e. PLC, HMI, I/O boards, etc.) and pneumatics 215 a, 215 b components wherein the compartment 207 a is isolated from a fluids compartment 207 b having the deionized water 215 c, city water 215 d and fluid dispense line 217 connections. The day tank module 211 may be positioned at the end. A second identically configured system may also be positioned next to the first system. The supply drums 213 may sit on a pallet next to each of the systems. In a system having three engines 201, 203, 205 (see FIG. 10( b)) the engines could be positioned next to each other with the day tank 211 on the end. In this configuration, the modules 201, 203, 205 and 211 would all be accessible on the same side. Thus, the back of a second system having the identical configuration would be positioned abutting the back of the first system as shown in FIG. 10( b). The drums 213 may be placed on a pallet near the engine 201. Other configurations of the system are shown in FIGS. 10( c)-10(e).

The present invention as described above and shown in the embodiments of FIGS. 2-10 provides a cost effective and reliable solution to distributing semiconductor process fluids. It is anticipated that other embodiments and variations of the present invention will become readily apparent to the skilled artisan in light of the foregoing description and examples, and it is intended that such embodiments and variations likewise be included within the scope of the invention as set forth in the following claims. 

1. A fluid distribution system for supplying fluid to a point of use comprising: a fluid source; a first engine adapted to receive fluid from the fluid source and to distribute fluid to the point of use; and a second engine identical to the first engine, the second engine being adapted to receive fluid from the fluid source and to distribute fluid to the point of use; wherein the fluid distribution system does not have any single point failures.
 2. The fluid distribution system of claim 1 having no planned downtime wherein the system is adapted to distribute fluid to the point of use while maintenance is performed on any component of the system.
 3. The fluid distribution system of claim 1 further comprising a third engine identical to the first and second engines wherein the third engine is adapted to receive fluid from the fluid source and to distribute fluid to the point of use.
 4. The fluid distribution system of claim 1 wherein the first and second engines comprise a pump and a pressure vessel.
 5. The fluid distribution system of claim 4 wherein the pressure vessel comprises a level sensor.
 6. The fluid distribution system of claim 4 wherein the pressure vessel comprises a load cell.
 7. The fluid distribution system of claim 1 wherein the first and second engines comprise a positive displacement pump and a pulse dampener.
 8. The fluid distribution system of claim 1 wherein the first and second engines comprise a centrifugal pump.
 9. The fluid distribution system of claim 1 wherein the first and second engines comprise a pressure vacuum vessel.
 10. The fluid distribution system of claim 9 wherein each of the pressure vacuum vessels comprises a sensor.
 11. The fluid distribution system of claim 9 wherein each of the pressure vacuum vessels comprises a load cell.
 12. The fluid distribution system of claim 1 wherein the point of use is a semiconductor process tool.
 13. A fluid distribution system comprising: a main module; a day tank module; a fluid source; a point of use; a first engine adapted to receive fluid from each of the main module, the day tank module and the fluid source and adapted to dispense fluid to each of the day tank module, the fluid source and the point of use; and a second engine adapted to receive fluid from each of the main module, the day tank module and the fluid source and adapted to dispense fluid to each of the day tank module, the fluid source and the point of use; wherein the fluid distribution system does not have any single point failures.
 14. The fluid distribution system of claim 13 having no planned downtime wherein the system is adapted to distribute fluid to the point of use while maintenance is performed on any component of the system.
 15. The fluid distribution system of claim 13 further comprising a third engine adapted to receive fluid from each of the main module, the day tank module and the fluid source and adapted to dispense fluid to each of the day tank module, the fluid source and the point of use.
 16. The fluid distribution system of claim 13 further comprising a central processing unit having an input-output module connected to each of the first and second engines.
 17. The fluid distribution system of claim 13 further comprising a plurality of central processing units wherein each central processing unit comprises an input-output module connected to each of the first and second engines.
 18. The fluid distribution system of claim 13 wherein the first and second engines comprise a pump and a pressure vessel.
 19. The fluid distribution system of claim 18 wherein the pressure vessel comprises a level sensor.
 20. The fluid distribution system of claim 18 wherein the pressure vessel comprises a load cell.
 21. The fluid distribution system of claim 13 wherein the first and second engines comprise a positive displacement pump and a pulse dampener.
 22. The fluid distribution system of claim 13 wherein the first and second engines comprise a centrifugal pump.
 23. The fluid distribution system of claim 13 wherein the first and second engines comprise a pressure vacuum vessel.
 24. The fluid distribution system of claim 23 wherein each of the pressure vacuum vessels comprises a sensor.
 25. The fluid distribution system of claim 23 wherein each of the pressure vacuum vessels comprises a load cell.
 26. A method of distributing fluid to a point of use comprising: distributing fluid to the point of use with a first engine; filtering fluid in a day tank with a second engine; and filtering fluid in a supply drum with a third engine; wherein each of the first, second and third engines is adapted to perform the steps of distributing fluid to the point of use, filtering fluid in the day tank and filtering fluid in the supply drum.
 27. The method of claim 26 wherein in the event of failure of a component in the first engine, the second engine or the third engine is adapted to distribute the fluid to the point of use.
 28. The method of claim 26 further comprising the step of performing maintenance on a component of the fluid distribution system without requiring any planned downtime. 